Advice needed on stand-alone battery backup system

[Jackie-Hangman]

Hi guys,

As you can see, I'm new around here and would like to get your opinions/advice/suggestions on the following equipment and their viability as a trolley/cabinet system, charged from the grid only - something like a portable power station:

INVERTER: Growatt SPF 5000 ES | 5Kw | 48V
BATTERY: LiFeTIDE LiFePO4 | 51.2V | 100Ah | 5120Wh
AVS: Automatic Voltage Protector 60A
PRICE: $1600 (R30 000 - South African Rands)

Website page link


Some background

I'm from South Africa, as you can probably tell, and I am sure you have heard of the horror stories of the "Loadshedding" (a.k.a power failures) that we live with down here. I have some rather basic knowledge of batteries and inverters after reading a couple books, some posts on this forum and watching some videos on Youtube. The original plan was to assemble my own battery backup kit to get us through "loadshedding", using EVE prismatic cells, but then I recently saw the above mentioned equipment and thought it may be a better option for me with regards to time. We are currently renting and so don't really want to install anything permanent, plus I read there is apparently a 5 month wait to acquire permission to install solar power in my area, due to a backlog. Hence why we are looking at something more immediate and movable.


What we need from the system

How often will we need the system running: 2 - 3 times per day
How long will we need the system running for each time: Roughly 4 hours per session
Grid time available to recharge the battery between power failures: 4 hours
Our power consumption needs: 510 W per hour (basic needs) or 800 W per hour (ideal)
System location: In a corner of the lounge (negotiable)

The schedule changes all the time with regards to the power failures, but for the sake of this post I've just gone with 4 hours on and 4 hours off. I've also read that the inverter itself will consume about 65 W per hour. The average summer high temperature where I live is about 82.4 °F (28 °C) and the average winter low temperature is around 48.2 °F (9 °C).


What I'd like to know

1. Are Growatt and LiFeTIDE decent brands?
2. What are your opinions on the above mentioned equipment, in general and for the purpose (freestanding trolley/cabinet system with leads to appliances) that I'd like it for?
3. Is a 20% to 90% discharge/charge limit recommended for this battery or could I get away with 0% to 100% if needed, without compromising the battery life...taking into account it could experience 3 cycles per day?
4. Am I correct in assuming that I will be able to change the charge/discharge rate in the BMS with this system to 30A or 35A?
5. Will either the inverter or battery make a lot of noise at any time?
6. The battery specification sheet says it has a "built-in fire extinguisher", is this a real safety feature or a marketing trick of some sort?
7. On the battery spec sheet it also says "Test Condition: 80% DOD, 0.5C charge & discharge @25°C" at the bottom of the page...just to clarify, does this mean the tests were done from 100% down to 20% every time?

I'd really like to know your thoughts on this and if you feel there's something I should know or consider that I haven't mentioned, then please fire away.

 

[DIYrich]

Growatt is good. Don't know about battery.

Equipment seems fine. Maybe add solar panels later.

20-100% is fine. Maybe 10-100. Avoid 0%.

800w for 4 hours is 3200 kWh, or about 60% of your 5kwh battery. If you are recharging in 4 hours, you might want more battery to avoid charging too fast on a regular basis.

Don't know how noisy the growatt is. Loud when fans turn on to cool the unit.

Fire extinguisher is a gimmick. Hard to stop a lithium fire, but lifepo4 is low fire Hazzard.

 

[Jackie-Hangman]

Growatt is good. Don't know about battery.

Equipment seems fine. Maybe add solar panels later.

20-100% is fine. Maybe 10-100. Avoid 0%.

800w for 4 hours is 3200 kWh, or about 60% of your 5kwh battery. If you are recharging in 4 hours, you might want more battery to avoid charging too fast on a regular basis.

Don't know how noisy the growatt is. Loud when fans turn on to cool the unit.

Fire extinguisher is a gimmick. Hard to stop a lithium fire, but lifepo4 is low fire Hazzard.

Thanks for the info.

Yeah, the plan is to eventually permanently install this equipment with solar panels in our own place...and perhaps expand a bit.

You mention that I should perhaps get more battery to avoid charging too fast on a regular basis. Wouldn't setting the charge rate to 30A still be able recharge the used 3200 W in just over 2 hours, or do I have this all wrong?

 

[rodrick]

30 amp or .3c isn’t bad but you will have a longer life from you battery if you put a second battery in your system and that will drop it to a .15c your issue is you will be doing multiple charges unlike most of us doing a single charge daily

 

[chrisski]

I’d charge off what a spec sheet says. You will get thousands of charge cycles out of a battery. Likely that spec sheet was built for a 1c or .5c rate.

If you’re limiting yourself to .1c, then that is lead acid territory. Also can force you to get a bigger battery pack to charge 3.2 kWh in a couple hours.

Also, batteries are very expensive for any useable amount for a house. IMO, the cost could justify charging at the specked rate. A battery pack can be $10k per 10kWh installed. DIY and not following code can be done for a bit cheaper.

The ones I use have a recommended charge rate of .3 c.

 

[Jackie-Hangman]

I’d charge off what a spec sheet says. You will get thousands of charge cycles out of a battery. Likely that spec sheet was built for a 1c or .5c rate.

If you’re limiting yourself to .1c, then that is lead acid territory. Also can force you to get a bigger battery pack to charge 3.2 kWh in a couple hours.

Also, batteries are very expensive for any useable amount for a house. IMO, the cost could justify charging at the specked rate. A battery pack can be $10k per 10kWh installed. DIY and not following code can be done for a bit cheaper.

The ones I use have a recommended charge rate of .3 c.

Yeah, I think I may just stick with 0.3C if I go with this. On the spec sheet it says the tests were done at 0.5C and the recommended charging current is between 30A to 50A.

Thanks for the info guys

 

[DIYrich]

The fastest charging is between 20-80%. At 3 cycles per day, at least one charge cycle is 8 hours long. That is important to get back to 100% on a regular basis.

Sizing battery for 4 hours of load is small. Many systems are 18 hours or more.

If the plan is to expand, consider sizing the inverter for your future needs.

I suggest buying the batteries as you planned to get through the unstable power. Next would be to add panels to save money on not purchasing power and stabilize daytime running. That will give you more money to expand batteries.

 

[Jackie-Hangman]

The fastest charging is between 20-80%. At 3 cycles per day, at least one charge cycle is 8 hours long. That is important to get back to 100% on a regular basis.

Sizing battery for 4 hours of load is small. Many systems are 18 hours or more.

If the plan is to expand, consider sizing the inverter for your future needs.

I suggest buying the batteries as you planned to get through the unstable power. Next would be to add panels to save money on not purchasing power and stabilize daytime running. That will give you more money to expand batteries.

Good advice, Rich...I'll definitely look into that.

Thanks